Experimental functions to collect and display timing data for cluster
computations.
Usage
snow.time(expr)
## S3 method for class 'snowTimingData'
print(x, ...)
## S3 method for class 'snowTimingData'
plot(x, xlab = "Elapsed Time", ylab = "Node",
title = "Cluster Usage", ...)
Arguments
expr
expression to evaluate
x
timing data object to plot or print
xlab
x axis label
ylab
y axis label
title
plot main title
...
additional arguments
Details
snow.time collects and returns and returns timing information
for cluster usage in evaluating expr. The return value is an
object of class snowTimingData; details of the return
value are subject to change. The print method for
snowTimingData objects shows the total elapsed time, the total
communication time between master and worker nodes, and the compute
time on each worker node. The plot, motivated by the display
produced by xpvm, produces a Gantt chart of the computation, with
green rectangles representing active computation, blue horizontal lines
representing a worker waiting to return a result, and red lines
representing master/worker communications.
Examples
## Not run:
cl <- makeCluster(2,type="SOCK")
x <- rnorm(1000000)
tm <- snow.time(clusterCall(cl, function(x) for (i in 1:100) sum(x), x))
print(tm)
plot(tm)
stopCluster(cl)
## End(Not run)